Risks of Using Raw Pointers in C++

In C++, raw pointers are variables that hold memory addresses of other variables or dynamically allocated memory. While raw pointers provide powerful low-level control over memory, they also introduce several risks that can lead to bugs, security vulnerabilities, and crashes.

What is a Raw Pointer?

A raw pointer is a basic pointer type that directly stores the address of a memory location.

Example:

int x = 10;

// ptr holds address of x
int* ptr = &x;

Common Risks of Using Raw Pointers

Let’s look at the key dangers of raw pointers in C++:

Memory Leaks

Raw pointers require manual deallocation of dynamically allocated memory using delete or delete[]. If you forget to free memory, it leads to memory leaks — memory that is allocated but never released.

#include <iostream>
using namespace std;

int main() {
    
    // Allocate memory for an integer
    int* p = new int(42);
    
    // Use the pointer
    cout << "Value: " << *p;

    // Forgot to delete p — memory leak happens
    // delete p;  // This is missing

    return 0;
}

Value: 42

Over time, this leaks memory and can exhaust system resources, especially in long-running programs.

Dangling Pointers

A dangling pointer points to memory that has been deallocated or gone out of scope.

#include <iostream>
using namespace std;
int main() {
    int* p = new int(99);
    
    // Memory freed
    delete p;
    
    // p still points to the freed memory 
    cout << "Dangling value (undefined): " << *p;

    return 0;
}

Dangling value (undefined): 0

Using a dangling pointer may result in crashes, data corruption, or unpredictable behaviour.

Double Deletion

If you delete the same pointer twice, the program’s behaviour is undefined.

#include <iostream>

int main() {
    int* p = new int(7);
    
    // First delete — OK
    delete p;
    
    // Second delete — undefined behavior
    delete p;

    return 0;
}

Output

bort signal from abort(3) (SIGABRT)
*** Error in `./Solution': double free or corruption (fasttop): 0x0000000006382c20 ***
timeout: the monitored command dumped core
/bin/bash: line 1:    31 Aborted  

Wild Pointers

A wild pointer is a pointer that is not initialized but is used anyway.

#include <iostream>
using namespace std;

int main() {
    
    // Uninitialized pointer (wild)
    int* p;
    
    // Dangerous: writing to an unknown address
    *p = 10;

    cout << "Written to wild pointer";

    return 0;
}

Written to wild pointer

Ownership Confusion / Aliasing Example

When multiple raw pointers point to the same dynamically allocated memory, it's unclear who is responsible for deleting it.

#include <iostream>
using namespace std;
int main() {
    int* p1 = new int(100);
    
    // Both point to same memory
    int* p2 = p1;
    
    // Memory freed
    delete p1;
    
    // p2 still points to freed memory — dangling
    cout << "p2 value (undefined): "
    << *p2;

    // If we delete p2, we attempt to free
    // same memory again undefined behavior
    delete p2;

    return 0;
}

Output

Abort signal from abort(3) (SIGABRT)
*** Error in `./Solution': double free or corruption (fasttop): 0x0000000025d57c20 ***
timeout: the monitored command dumped core
/bin/bash: line 1:    32 Aborted

This makes memory management error-prone and invites bugs like double deletion or dangling pointers.

No Bounds Checking

Raw pointers do not provide array bounds checking when used for dynamic arrays.

#include <iostream>
using namespace std;

int main() {
    int* arr = new int[3]{1, 2, 3};
    
    // Correct access
    cout << "arr[0]: " << arr[0] << endl;
    
    // Undefined behavior — writing beyond
    // array size
    arr[5] = 42;

    cout << "Out-of-bounds write done";

    delete[] arr;
    return 0;
}

arr[0]: 1
Out-of-bounds write done

Overwriting adjacent memory may corrupt data or crash the program.